a, b, c = input().split()
a, b = int(a), int(b)
if c == "W":
    d = "B"
else:
    d = "W"
for i in range(b):
    for j in range(a):
        if (i + j) % 2 == 0:
            print(c, end="")
        else:
            print(d, end="")
    print("")